Andrea Tantaros in 2015. The former anchor sued Fox News in August, accusing the network of retaliation after she complained about sexual harassment. Credit Charles Sykes/Invision, via Associated Press

The United States attorney’s office is looking into the way Fox News handled payments related to sexual harassment cases to determine whether the company misled investors, according to the lawyer for a woman who is suing the network.

At a hearing in New York State Supreme Court on Wednesday, the lawyer, Judd Burstein, who is representing the former Fox anchor Andrea Tantaros, said that another one of his clients had received a grand jury subpoena related to Fox News. He did not identify that client.

Mr. Burstein said in a text message that he believed federal investigators were looking at whether Fox News structured sexual harassment settlement claims by paying them out in salaries, “so as not to have to report them.”

He added that the prosecutors had identified themselves as being from a securities fraud division of the United States attorney’s office in Manhattan.

In a statement, Fox News said it had not received a subpoena but had “been in communication with the U.S. attorney’s office for months.” The statement added that Fox “will continue to cooperate on all inquiries with any interested authorities.”

The United States attorney’s office declined to comment.

The prospect of a criminal investigation is a surprising escalation of the sexual harassment scandal that engulfed Fox News over the summer and led to the departure of its chairman, Roger Ailes. After reaching a $20 million settlement with Gretchen Carlson, a former anchor who sued Mr. Ailes, and conducting an internal investigation into his conduct, the company tried hard to put the episode behind it.

The scope of the investigation by the United States attorney’s office, which appeared to be in the early stages, was not immediately clear. Mr. Burstein made the remarks while he was arguing that Ms. Tantaros’s case — she sued the network in August, accusing Fox News of retaliation after she complained about sexual harassment — should go forward in an open court. A judge rejected that claim on Wednesday and ruled that her case would be resolved in arbitration.
In a statement, a spokeswoman for Fox News said, “The court granted Fox News’s motion to send Andrea Tantaros’s case to arbitration, where it always belonged, and rejected her counsel Judd Burstein’s histrionics.”

Asked whether Mr. Ailes had received a subpoena, Susan Estrich, his lawyer, declined to comment. Mr. Ailes has denied the sexual harassment allegations.
Ms. Tantaros’s suit asserts that the network’s newsroom resembled “a sex-fueled, Playboy Mansion-like cult.” The suit named a number of Fox News executives in addition to Mr. Ailes, accusing them of marginalizing her and removing her from the air after she complained.

Fox News denied the charges, saying that Ms. Tantaros was let go for violating her contract by writing a book without approval.

In July, Ms. Carlson sued Mr. Ailes for sexual harassment. Fox News’s parent company, 21st Century Fox, hired the law firm Paul, Weiss, Rifkind, Wharton & Garrison to conduct an investigation, and a number of other women stepped forward with similar accusations, including the former Fox star Megyn Kelly.